Assembly for producing alkylene oxides and glycol ethers

ABSTRACT

There is provided a manufacturing assembly for the production of an alkylene oxide and a stream of glycol ethers. The manufacturing assembly produces the alkylene oxide and stream of glycol without the use of equipment for separating substantially all of the alkyl alcohol from the alkylene oxide product stream. Thus, the use of additional pieces of equipment can be avoided, or the equipment required to effectuate any required further separation and/or purification may be smaller and/or cheaper to purchase and/or operate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. patent application Ser. No.14/806,498, now issued as U.S. Pat. No. 9,273,019, filed Jul. 22, 2015,which, in turn is a divisional application of U.S. patent applicationSer. No. 13/808,594, filed Jan. 6, 2013, now issued as U.S. Pat. No.9,169,226, which, in turn, is a 371 of International Application No.PCT/US2011/42107, now published as WO 2012/009155, filed Jun. 28, 2011,which, in turn, claims the benefit of U.S. provisional patentapplication Ser. No. 61/364,231, filed Jul. 14, 2010. The contents ofthe aforementioned applications are incorporated herein by reference intheir entirety.

FIELD

The present invention relates to manufacturing assemblies for theproduction of an alkylene oxide and one or more glycol ethers. A processfor manipulating the amount of an alkyl alcohol in a product streamcomprising an alkylene oxide and a process for producing an alkyleneoxide and one or more glycol ethers incorporating the process is alsoprovided.

BACKGROUND

Alkylene oxides may be prepared by reaction of an alkylene and hydrogenperoxide, hydroperoxide, or oxygen and hydrogen. Generally, thesereactions are carried out in a liquid solvent, e.g., an alkyl alcoholand water, and in the presence of a solid, metal containing catalyst.However, the use of one or more alkyl alcohols as a solvent can beproblematic in that the separation of the same from the desired alkyleneoxide requires energy intensive distillation operations comprising alarge number of trays, and operated at high reflux rates. In order toreduce the economic burden imposed by the use of the alkyl alcohol, amajority, if not all, of the alkyl alcohol may typically be recycledonce separated from the alkylene oxide.

In order to further reduce this burden, alternative separationtechniques have been proposed, many involving the use of extractivedistillation. However, the proposed solutions often introduce additionalproblems. For example, the addition of an extraction solvent increasesthe size requirement of the distillation column used to remove the alkylalcohol due to the added volume of the extraction solvent.

Desirably, methods for the production of alkylene oxide would bedeveloped that provide for the separation of an alkyl alcohol from analkylene oxide with reduced difficulty and/or economic burden ascompared to conventional or extractive distillation methods.

BRIEF DESCRIPTION

The present invention provides such a process. More specifically, thepresent invention provides a process for manipulating the amount of analkyl alcohol in a mixture, e.g., such as an alkylene oxide productstream. More particularly, and in contrast to conventional processeswherein substantially all of the alkyl alcohol must be separated anddesirably recycled, in the present process, a greater amount of alkylalcohol may be allowed to remain in a partially refined alkylene oxideproduct stream. The residual alkyl alcohol is subsequently substantiallyentirely reacted to form one or more downstream products, e.g., one ormore glycol ethers, which are more easily separated from the alkyleneoxide product stream. Indeed, the amount of alkyl alcohol in thepartially refined alkylene oxide product stream can be selected basedupon the output of the desired one or more glycol ethers, if desired.Advantageously, the volume of feed to the alkylene oxide refiningprocess is not increased, as may be the case when extractivedistillation techniques are utilized to achieve a similar purpose.Furthermore, because the use of extractive distillation can be avoided,the capital and energy costs associated with the same are alsoeliminated.

In one aspect then, the present invention provides a process formanipulating the amount of an alkyl alcohol in a mixture, wherein themixture comprises from about 5 to about 15 weight percent alkyleneoxide, about 50 to about 85 weight percent alkyl alcohol and about 10 toabout 25 weight percent water. The process comprises introducing themixture into a distillation column to produce a refined streamcomprising from about 50 to about 99 weight percent alkylene oxide,about 0.5 to about 50 weight percent alkyl alcohol and about 0 to about5 weight percent water. In some embodiments, the refined stream maycomprise from about 65 to about 99 weight percent alkylene oxide, about0.5 to about 35 weight percent alkyl alcohol and about 0 to about 5weight percent water. The refined stream is then reacted with a catalystcomprising a metal-ligand complex, an acid, a base, a metal alkoxide, ora combination of any number of these to reduce the alkyl alcohol contentin a resulting reacted stream to less than 1 wt %.

Such a mixture may typically be found in, e.g., an alkylene oxideproduct stream, and so, the process may advantageously be incorporatedinto processes for the production of an alkylene oxide and one or moreglycol ethers. In a further aspect, the present invention thus providesa process for the preparation of an alkylene oxide and one or moreglycol ethers. The process comprises reacting an alkylene with hydrogenperoxide, a hydroperoxide, or hydrogen and oxygen under conditionssufficient to produce a product stream comprising the desired alkyleneoxide. The process comprises introducing the mixture into a distillationcolumn to produce a refined stream comprising from about 50 to about 99weight percent alkylene oxide, about 0.5 to about 50 weight percentalkyl alcohol and about 0 to about 5 weight percent water. In someembodiments, the refined stream may comprise from about 65 to about 99weight percent alkylene oxide, about 0.5 to about 35 weight percentalkyl alcohol and about 0 to about 3 weight percent water. The refinedproduct stream is then reacted with a catalyst comprising a metal-ligandcomplex, an acid, a base, or a combination of any number of these toproduce a reacted stream comprising less than 1 wt % alkyl alcohol, fromabout 0.5 to about 98 weight percent alkylene oxide and from about 2 toabout 99 weight percent glycol ethers. The refined, reacted productstream is then introduced into a second distillation column to provide asubstantially pure stream of alkylene oxide and a stream of glycolethers.

Because the present processes allow for the presence of a greater amountof alkyl alcohol in the partially refined alkylene oxide stream thanconventional processes, and indeed for the manipulation of the samebased upon the desired production of glycol ethers, the use ofseparation techniques capable of separating substantially all of thealkyl alcohol from the alkylene oxide product stream are not required.And so, the use of additional pieces of equipment can be avoided, or theequipment required to effectuate any required further separation and/orpurification may be smaller and/or cheaper to purchase and/or operate.Furthermore, the operation of a second reaction step in the process bothproduces a substantially pure stream of alkylene oxide and asubstantially pure stream of useful glycol ethers. And so, in anotheraspect, a hybrid manufacturing assembly for the production of analkylene oxide and a stream of glycol ethers is provided.

The hybrid manufacturing assembly comprises a reactor appropriate forhousing a reaction to produce an alkylene oxide product streamcomprising from about 5 to about 15 weight percent alkylene oxide, about50 to about 85 weight percent alcohol and about 10 to about 25 weightpercent water. The assembly further comprises a distillation columnoperatively disposed relative to the reactor to receive the alkyleneoxide product stream thereof, comprising fewer than 80 theoreticalstages and appropriate for producing a refined stream comprising fromabout 50 to about 99 weight percent alkylene oxide, about 0.5 to about50 weight percent alkyl alcohol and about 0 to about 5 weight percentwater, or from about 65 to about 99 weight percent alkylene oxide, about0.5 to about 35 weight percent alkyl alcohol and about 0 to about 5weight percent water. The assembly also comprises a vessel operativelydisposed relative to the distillation column to receive the refinedstream therefrom and housing a catalyst capable of reacting with therefined stream to produce a reacted stream comprising less than 1 wt %alkyl alcohol, from about 0.5 to about 98 weight percent alkylene oxideand from about 2 to about 99 weight percent glycol ethers. Finally, thehybrid assembly comprises a second distillation column operativelydisposed relative to the vessel to receive the reacted stream to producea substantially pure stream of alkylene oxide and a stream of glycolethers.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings,wherein:

FIG. 1 is a schematic illustration of a manufacturing assembly accordingto one embodiment.

DETAILED DESCRIPTION

The present specification provides certain definitions and methods tobetter define the present invention and to guide those of ordinary skillin the art in the practice of the present invention. Provision, or lackof the provision, of a definition for a particular term or phrase is notmeant to imply any particular importance, or lack thereof. Rather, andunless otherwise noted, terms are to be understood according toconventional usage by those of ordinary skill in the relevant art.

The terms “first”, “second”, and the like, as used herein do not denoteany order, quantity, or importance, but rather are used to distinguishone element from another. Also, the terms “a” and “an” do not denote alimitation of quantity, but rather denote the presence of at least oneof the referenced item, and the terms “front”, “back”, “bottom”, and/or“top”, unless otherwise noted, are merely used for convenience ofdescription, and are not limited to any one position or spatialorientation.

If ranges are disclosed, the endpoints of all ranges directed to thesame component or property are inclusive and independently combinable(e.g., ranges of “up to about 25 wt. %, or, more specifically, about 5wt. % to about 20 wt. %,” is inclusive of the endpoints and allintermediate values of the ranges of “about 5 wt. % to about 25 wt. %,”etc.). Furthermore, weight percents are used to define many of theranges herein. Although these ranges are expected to include many of theembodiments of the invention, they were calculated based upon oneembodiment, i.e., that embodiment wherein the alkyl alcohol is methanoland the alkylene oxide comprises propylene oxide. Those of ordinaryskill in the art will recognize that these ranges may vary if differentmembers of these genus' are utilized.

The modifier “about” used in connection with a quantity is inclusive ofthe stated value and has the meaning dictated by the context (e.g.,includes the degree of error associated with measurement of theparticular quantity). Unless otherwise defined, all percents areprovided as weight percents. The suffix “(s)” as used herein is intendedto include both the singular and the plural of the term that itmodifies, thereby including one or more of that term (e.g., “thecatalyst(s)” may include one or more catalysts). Reference throughoutthe specification to “one embodiment”, “another embodiment”, “anembodiment”, and so forth, means that a particular element (e.g.,feature, structure, and/or characteristic) described in connection withthe embodiment is included in at least one embodiment described herein,and may or may not be present in other embodiments. In addition, it isto be understood that the described inventive features may be combinedin any suitable manner in the various embodiments.

The present invention provides a process for manipulating the amount ofan alkyl alcohol in a mixture, e.g., such as a partially refinedalkylene oxide product stream. More particularly, and in contrast toconventional processes wherein substantially all of the alkyl alcoholmust be separated and desirably recycled, in the present process, agreater amount of alkyl alcohol may be allowed to remain in a partiallyrefined alkylene oxide product stream. The residual alkyl alcohol issubsequently substantially entirely reacted to form one or moredownstream products, e.g., one or more glycol ethers, which is/are moreeasily separated from the alkylene oxide product stream. In suchembodiments, overall process yield/specificity may advantageously beincreased.

The mixture subjected to the present process may be any mixture whereinthe alkyl alcohol content thereof is desirably manipulated, e.g.,reduced, without application of conventional and/or extractivedistillation processes, which can add extra cost to the process in thatthe extraction solvent typically must later be removed and optionallyrecovered and recycled. Exemplary mixtures that find particular benefitin application of the present process include those that comprise notonly a relatively high amount, e.g., greater than about 50 wt %, orgreater than about 60 wt % or greater than 70 wt % or even greater thanabout 85 wt %, of an alkyl alcohol, but also amounts of alkylene oxideand water.

More particularly, the mixture to which the process may advantageouslybe applied may comprise from about 5 to about 15 weight percent alkyleneoxide, about 50 to about 85 weight percent alkyl alcohol and about 10 toabout 25 weight percent water, based upon the total weight of themixture. Or, the mixture may comprise from about 6 to about 12 weightpercent alkylene oxide, about 60 to about 80 weight percent alkylalcohol and about 10 to about 20 weight percent water. In someembodiments, the process described herein may even be applied tomixtures comprising from about 8 to about 10.5 weight percent alkyleneoxide, about 65 to about 75 weight percent alkyl alcohol and about 10 toabout 15 weight percent water.

The mixture may comprise any alkyl alcohol desirably separated from sucha mixture. Desirably, the alkyl alcohol to be separated will be onetypically present in mixtures also comprising amounts of one or morealkylene oxides. Alkyl alcohols typically present in mixtures alsocomprising one or more alkylene oxides generally include methanol,ethanol, propanol, butanol, pentanol, hexanol, 2-ethylhexyl alcohol, orcombinations of any of these. In some processes for the production ofalkylene oxides, methanol may typically be used as a solvent and thus,in some embodiments, the alkyl alcohol may advantageously comprisemethanol.

The mixture also comprises at least one alkylene oxide. Any alkyleneoxide may be present, and typical alkylene oxides are exemplified by,but are not limited to, ethylene oxide, propylene oxide, butylene oxide,pentylene oxide, hexylene oxide and combinations thereof. In someembodiments, the alkylene oxide(s) may comprise ethylene oxide,propylene oxide, butylene oxide or combinations of these. Because of itscommercial importance and widespread use in the production of glycolethers, in some embodiments, the alkylene oxide may desirably comprisepropylene oxide.

Whatever the desired mixture, it is initially introduced into adistillation column to provide a more concentrated stream of alkyleneoxide. The refined stream will desirably comprise from about 50 to about99 weight percent alkylene oxide, about 0.5 to about 50 weight percentalkyl alcohol and about 0 to about 5 weight percent water. In someembodiments, e.g., wherein the alkyl alcohol comprises methanol and thealkylene oxide comprise propylene oxide, the refined stream may comprisefrom about 65 to about 99 weight percent alkylene oxide, about 0.5 toabout 35 weight percent alkyl alcohol and about 0 to about 5 weightpercent water. Or, in such embodiments, the refined stream may comprisefrom about 70 to about 95 weight percent alkylene oxide, from about 1weight percent to about 30 wt % alkyl alcohol and from about 0.1 weightpercent to about 4.9 wt % water. Or, the refined stream may comprisefrom about 70 to about 90 wt % alkylene oxide, from about 10 weightpercent to about 30 wt % alkyl alcohol and from about 1 weight percentto about 4 wt % water.

Generally speaking, the distillation operation may comprise fewer than80 theoretical stages, and may comprise, e.g., from about 15 to about 70theoretical stages, or from about 30 to about 60 theoretical stages.Conventional distillation process utilized to separate such mixtures maytypically require the utilization of 80 or more stages, and so, byvirtue of the application of the principles described herein, thetheoretical stages, and energy input, required to conduct the separationcan be reduced. One or more columns may be utilized that provide thedesired total number of stages/plates, and in some embodiments, onecolumn may be sufficient, while also provide space, energy and capitalsavings.

The distillation column utilized to provide the refined stream willfurther desirably have a bottoms temperature of from about 40° C. toabout 70° C., or from about 46° C. to about 64° C., or from about 52° C.to about 62° C. The distillation may be carried out at pressures of fromabout 300 mbar to about 1000 mbar, or from about 400 mbar to about 800mbar, or from about 500 mbar to about 700 mbar, as measured at the topof the column. Suitable combinations of temperature and pressure for thedistillation include from about 40° C. to about 70° C. and from about300 mbar to about 1000 mbar, or from about 46° C. to about 64° C. andfrom about 400 mbar to about 800 mbar, or from about 52° C. to about 62°C. and from about 500 mbar to about 700 mbar.

The refined stream is then reacted with a catalyst to reduce the alkylalcohol content in a resulting reacted stream to less than 1 wt %. Moreparticularly, the reacted stream may comprise less than 1 wt % alkylalcohol, from about 0 wt % to about 98 wt % alkylene oxide, and fromabout 2 wt % to about 99 wt % glycol ethers, or less than about 0.8 wt %alkyl alcohol and from about 10 wt % to about 90 wt % alkylene oxide,and from about 10 wt % to about 90 wt % glycol ethers, or less thanabout 0.7 wt % alkyl alcohol and from about 50 wt % to about 85 wt %alkylene oxide, and from about 15 wt % to about 50 wt % glycol ethers.

The particular glycol ethers obtainable will depend upon the particularcomposition of the starting mixture, i.e., the particular alkyl alcoholand alkylene oxide in the mixture, as well as the particular catalystchosen. For mixtures comprising, e.g., methanol and propylene oxide, thestream of glycol ethers may typically comprise dipropylene glycolmonomethyl ether (DPM) and monopropylene glycol methyl ethers (PM). Insome particularly advantageous embodiments of the present method, thecatalyst utilized to react with the refined stream can provide a greaterpercentage of the PM homologue in the glycol ethers stream than DPM,e.g., the reacted stream may comprise greater than 90%, or greater than95% or even greater than 98% of PM, and less than 10%, or even less than5% or even less than 2% DPM.

Further advantageous is the fact that the PM homologue typically furthercomprises greater than 95%, or greater than 97%, or even greater than99% or even greater than 99.7% 1-methoxy-2-propanol (PM2) and less than5%, or less than 3%, or less than 1%, or even less than 0.3%2-methoxy-1-propanol (PM1). PM2 is not only easily separated frompropylene oxide with minimal theoretical stages, but also, is easilyprovided into salable product specifications via the same. SeparatingPM1 from PM2 to the levels required to provide a salable PM2 product canbe difficult and costly, since distillation is used to separate thesesimilar boiling materials (PM2 boiling point at 1 atm (bp)=118-119° C.;PM1 bp=130° C.).

And so, the catalyst utilized is desirably one exhibiting a highactivity and/or high selectivity in the alkanolysis of alkylene oxide.Such catalysts include, but are not limited to, acidic, basic, andneutral catalytic species as well as metal-ligand complexes. Thecatalyst can be heterogenous or homogenous. Suitable catalysts aredisclosed, for example in, K. Tanabe, M. Misono, Y. Ono, H. Hattori“Studied in Surface Science and Catalysis. New Solid Acids and Bases:Their Catalytic Properties” 1989, Vol. 51. pp. 1-3. H. Hattori“Heterogeneous Basic Catalysts” Chem. Rev. 1995, 95, 537-558, U.S. Pat.No. 4,360,698 to Sedon, and U.S. Pat. No. 2,807,651 to Britton, each ofthese being incorporated herein by reference in its entirety for any andall purposes.

Examples of suitable acidic catalytic species include, but are notlimited to, metal triflates, metal tosylates, tris-perfluoronated arylborons, p-toluenesulfonic acid, phosphoric acid, sulfuric acid, boricacid, fluorine containing acids, chloric acids, acidic ion exchangeresin, acidic alumina, zeolites, acid modified silicas, aluminas, orsilica-aluminas, metal oxides and sulfides, mounted acids on silica,quartz sand, alumina or diatomaceous earth, mixed oxides, metal salts,heat treated charcoal, or combinations thereof. In some embodimentswherein the catalyst is desirably acidic, aluminum triflate maydesirably be used.

Examples of suitable basic catalytic species include, but are notlimited to, metal hydroxides, metal carbonates, metal oxides,substituted or unsubstituted imidazoles, substituted or unsubstitutedamines, substituted or unsubstituted pyridines, metal alkoxides, basicion-exchange resins, basic alumina, alkali ion-exchanged zeolites,hydrotalcites, chrysotile, sepiolite, KF supported on alumina,lanthanide imide, nitride on zeolite, or combinations thereof. In someembodiments, substituted or unsubstituted imidazole(s) and/or potassiumhydroxide and/or sodium hydroxide, may be used if use of a basiccatalyst is desired.

Furthermore, suitable metal-ligand complexes include, but are notlimited to, monomers according to Formula I:

wherein R₁, R₂, R₃, R₄, Y₁, Y₂, X₁, X₂, X₃, X₄, X₅, X₆, X₇, and X₈comprise, independently of one another, substituents selected from thegroup consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl,hydrocarbyl, hydroxyl, alkoxyl, amino, nitro, amide, phosphoryl,phosphonate, phosphine, carbonyl, carboxyl, silyl, ether, thioether,sulfonyl, selenoether, ketone, aldehyde, and ester;

or wherein two or more of R₁, R₂, R₃, R₄, Y₁, Y₂, X₁, X₂, X₃, X₄, X₅,X₆, X₇, and X₈ together form a ring selected from the group consistingof a carbocyclic ring and a heterocyclic ring, said ring having from 4to 10 atoms in the ring;

wherein R₅ group is selected from the group comprising a carbon-carbonbond, a methylene group, an ethylene group, an amine, an oxygen atom,and a sulfur atom;

wherein M^(t+) is a Group 2-15 metal capable of complexing with a ligandto affect catalysis, wherein t is an integer between 2 and 4;

wherein group A is selected from the group consisting of neutral group,bound anionic group, unbound anionic group, and combinations thereof,wherein s is the number of A groups associated with the metal and is aninteger between 0 and 2.

In some embodiments of the invention, M is cobalt and A comprisescarboxylate, sulfonate, halide, alkoxide, hexafluorophosphate,tetrafluoroborate, hexafluoroantimonate or bis(trialkylsilyl)amide. Inone particular embodiment of the invention, A is 3-nitrobenzenesulfonateand s=1.

In some embodiments, one or more of R₁, R₂, R₃, R₄, Y₁, Y₂, X₁, X₂, X₃,X₄, X₅, X₆, X₇, and X₈ may be capable of providing a complementaryinteraction with a second monomer, either according to formula I orotherwise, to form a component selected from the group consisting ofoligomer, polymer, and copolymer. For example, in some embodiments, themetal-ligand complex may comprise an oligomer comprising from about 1 toabout 20 repeating units of the monomer.

In some embodiments, the metal-ligand complex is bound to a support.Examples of supports that can be used include, but are not limited to,an organic polymer, an ion-exchange resin, an inorganic support, a metalorganic framework, and carbon. The catalyst can be incorporated into oronto the support by any suitable method known to those skilled in theart including, but not limited to, covalent bonding, ionic bonding,hydrogen bonding, metal complexing, encapsulating, and intercalating.

The following documents provide examples of supporting techniques andtheir entire contents are hereby incorporated herein by reference forany and all purposes: Baleizo, et. al. Chemical Reviews 2006, 106(9),3987-4043; Orejón, et al., Industrial and Engineering Chemical Research2008, 47(21), 8032-8036; Yang, et al., Journal of Catalysis 2007, 248,204-212; Kim, et. al., Catalysis Today 2000, 63, 537-547.

Any of the above catalysts can be incorporated into polymeric structuresby utilizing any of several different methods known to those of ordinaryskill in the art. The following documents provide examples of suchtechniques: Hu, et al., Journal of Applied Polymer Science 2006, 101,2431-2436 Song, et al., Tetrahedron Letters 2003, 44, 7081-7085, Kwon,et al., Catalysis Today 2003, 87, 145-151, Gill, et al., Chemistry—AEuropean Journal 2008, 14, 7306-7313, Zheng, et al., Chemistry—AEuropean Journal 2006, 12, 576-583, Zheng, et al., Advanced Synthesisand Catalysis 2008, 350, 255-261. Each of these is incorporated byreference herein in their entirety for any and all purposes.

If desired, a cocatalyst may be used in the process. Generally, suitablecocatalysts comprise Lewis acid(s). Examples of Lewis acids that can beused, if desired, include, but are not limited to metal triflates, metaltosylates, tris-perfluoronated aryl boron, metal halides, andcombinations thereof. One non-limiting example of a metal triflate thatcan be used is aluminum triflate. When a cocatalyst is used, the moleratio of the catalyst (and in those embodiments wherein the catalyst isthe monomer above, the mole ratio of the monomeric unit) to theco-catalyst is generally in the range of from about 1:1 to about 20:1.

The refined stream is reacted with the desired catalyst under reactionconditions appropriate given the composition of the refined stream andthe chosen catalyst. Generally speaking, suitable reaction conditionsmay comprise a temperature in the range of from about −10° C. to about200° C., or from about 0° C. to about 150° C., or from about 10° C. toabout 100° C., or from about 15° C. to about 60° C. The reaction maytake place in any suitable vessel or zone, including a fixed bed, afluidized bed, a continuous stirred tank reactor (CSTR), batch,semi-batch, continuous types or combinations thereof. The desired vesselcan be operated isothermally, adiabatically, or a combination thereof.

In some embodiments, the reacted stream may be provided to a seconddistillation column to provide a substantially pure stream of alkyleneoxide and a stream of glycol ethers. In some embodiments, the alkyleneoxide may be propylene oxide, and the stream of glycol ethers maycomprise substantially PM2.

Those of ordinary skill in the art will be capable of determining thedistillation conditions capable of producing a stream of substantiallypure alkylene oxide and a stream of glycol ethers from the reactedstream, described above, the parameters of distillation being well knownin the art. One or more columns may be utilized that provide the desiredtotal number of stages/plates, and thus, the desired separation, and insome embodiments, one column may be sufficient, while also providingspace, energy and capital savings.

By utilizing the present process, the volume of feed into a process forthe production of alkylene oxide is not increased, in contrast tomethods that rely on, e.g., extractive distillation to achieve a similarpurpose. Furthermore, since no volume is added in the present process,it need not later be separated from the desired product stream as isrequired with conventional processes that may employ, e.g., extractivedistillation. Because the use of extractive distillation can be avoided,the capital and energy costs associated with the same are alsoeliminated. Additionally, the present process provides a flexible methodfor converting a part of the propylene oxide to a higher value glycolether product. And, for mixtures comprising, e.g., methanol andpropylene oxide, the stream of glycol ethers may typically comprisegreater than 90%, or greater than 95% or even greater than 98% ofmonopropylene glycol methyl ethers (PM), and less than 10%, or even lessthan 5% or even less than 2% dipropylene glycol monomethyl ether (DPM).Advantageously, the PM homologue typically further comprises greaterthan 95%, or greater than 97%, or even greater than 99% or even greaterthan 99.7% 1-methoxy-2-propanol (PM2) and less than 5%, or less than 3%,or less than 1%, or even less than 0.3% 2-methoxy-1-propanol (PM1). As aresult, the present process may advantageously be incorporated into aprocess for the production of an alkylene oxide and a stream of glycolethers.

The provided processes will generally comprise reacting an alkylene withhydrogen peroxide, hydroperoxide, or hydrogen and oxygen underconditions sufficient to produce a product stream comprising the desiredalkylene oxide. In some embodiments, the reaction will result in aproduct stream comprising from about from about 5 to about 15 weightpercent alkylene oxide, about 50 to about 85 weight percent alkylalcohol and about 10 to about 25 weight percent water, based upon thetotal weight of the mixture. Or, the product stream may comprise fromabout 6 to about 12 weight percent alkylene oxide, about 60 to about 80weight percent alkyl alcohol and about 10 to about 20 weight percentwater. In some embodiments, the product stream may even comprise fromabout 8 to about 10.5 weight percent alkylene oxide, about 65 to about75 weight percent alkyl alcohol and about 10 to about 15 weight percentwater.

Any alkylene may be reacted with the hydrogen peroxide, hydroperoxide,or oxygen and hydrogen, and the same may be selected based upon thealkylene oxide desirably produced. Suitable alkylenes include, forexample, ethylene, propylene, butylene, pentylene, hexylene, andcombinations thereof. In some embodiments, the alkylene oxide comprisespropylene oxide.

The term “hydroperoxide” refers to a compound of the formula ROOH,wherein R is any substituted or unsubstituted C₁-C₁₅ alkyl, aryl orarylalkyl group. Examples of hydroperoxides suitable for use in thepresent processes include, but are not limited to, tert-butylhydroperoxide, ethylbenzene hydroperoxide, tert-amyl hydroperoxide,cumene hydroperoxide, cyclohexyl hydroperoxide, methylcyclohexylhydroperoxide, tetrahydronapththalene hydroperoxide, isobutylbenzenehydroperoxide, ethylnaphthalene hydroperoxide, and peracids such asperacetic acid. Mixtures of two or more hydroperoxides can also be used.In some embodiments, hydrogen peroxide is reacted with the desiredalkylene. In such embodiments, the hydrogen peroxide is desirablyprovided as an aqueous hydrogen peroxide solution. Such a solution maycomprise hydrogen peroxide in a concentration of from about 1 to about90 wt %, or from about 10 to about 70 wt %, or from about 30 to about 50wt %, based upon the total weight of the solution.

The reaction of the desired alkylene and hydrogen peroxide,hydroperoxide or oxygen and hydrogen may desirably be carried out in thepresence of one or more catalysts. Suitable catalysts for epoxidationreactions include, but are not limited to, zeolites, and in particular,zeolites comprising titanium, e.g., titanium silicalites. In addition totitanium and silica, zeolite materials may comprise additional elements,such as, e.g., aluminum, zirconium, tin, iron, cobalt, nickel, gallium,boron, or fluorine. Zeolites comprising elements in place of titaniummay also be used. For example, zeolites wherein the titanium ispartially or completely replaced by vanadium, zirconium, niobium, ormixtures of these may be used.

In some embodiments, the zeolite catalyst comprises at least one oftitanium, germanium, tellurium, vanadium, chromium, niobium, zirconiumor combinations of these. In some embodiments, zeolite catalysts havinga pentasil zeolite structure. When the zeolite catalyst comprisestitanium such structures may include those assigned to structure typesITQ-4, ITQ-9, SSZ-24, TTM-1, UTD-1, CIT-1, CIT-5, ZSM-48, ZSM-12, MFI,MEL, MWW, BEA, TS-1, TS-2, TS3 or mixed structures of any of these, maybe used, as can zeolites displaying a structure that is amorphous tozeolite beta.

The product stream produced by the reaction of the desired alkylene withthe hydrogen peroxide, hydroperoxide, or hydrogen and oxygen in thepresence of a catalyst, if desired, is then introduced into adistillation column to produce a refined stream. Desirably, the refinedproduct stream will comprise from about 50 to about 99 weight percentalkylene oxide, about 0.5 to about 50 weight percent alkyl alcohol andabout 0 to about 5 weight percent water. In some embodiments, e.g.,wherein the alkyl alcohol comprises methanol and the alkylene oxidecomprise propylene oxide, the refined stream may comprise 65 to about 99weight percent alkylene oxide, about 0.5 to about 35 weight percentalkyl alcohol and about 0 to about 5 weight percent water. In suchembodiments, the refined stream may comprise from about 70 weightpercent to about 95 wt % alkylene oxide, from about 1 weight percent toabout 30 wt % alkyl alcohol and from about 0.1 weight percent to about4.9 wt % water. Or, the refined stream may comprise from about 70 weightpercent to about 90 wt % alkylene oxide, from about 10 weight percent toabout 30 wt % alkyl alcohol and from about 1 weight percent to about 4wt % water.

Generally speaking, the distillation column utilized to provide therefined stream may comprise fewer than 80 theoretical stages, and maycomprise, e.g., from about 15 to about 70 theoretical stages, or fromabout 30 to about 60 theoretical stages. The distillation columnutilized to provide the refined stream will further desirably have abottoms temperature of from about 40° C. to about 70° C., or from about46° C. to about 64° C., or from about 52° C. to about 62° C. Thedistillation may be carried out at pressures of from about 300 mbar toabout 1000 mbar, or from about 400 mbar to about 800 mbar, or from about500 mbar to about 700 mbar, as measured at the top of the column.

The refined product stream is then reacted with a catalyst comprising ametal-ligand complex, an acid, a base, or a combination of any number ofthese. Such catalysts are described above. The resulting reacted streamcomprises less than 1 wt % alkyl alcohol, from about 0.01 to about 98weight percent alkylene oxide and from about 2 to about 99 weightpercent glycol ethers.

The particular glycol ethers obtainable will depend upon the particularcomposition of the starting mixture, i.e., the particular alkyl alcoholand alkylene oxide in the mixture, as well as the particular catalystchosen. For exemplary mixtures comprising, e.g., methanol and propyleneoxide, the stream of glycol ethers may typically comprise greater than50%, or greater than 80% or even greater than 95% of monopropyleneglycol methyl ethers (PM), and less than 50%, or even less than 25% oreven less than 5% dipropylene glycol monomethyl ether (DPM). The PMhomologue typically further comprises greater than 95%, or greater than97%, or even greater than 99% or even greater than 99.7%1-methoxy-2-propanol (PM2) and less than 5%, or less than 3%, or lessthan 1%, or even less than 0.3% 2-methoxy-1-propanol (PM1).

In some embodiments, the reacted stream is then introduced into a seconddistillation column to provide a substantially pure stream of alkyleneoxide and a stream of glycol ethers. In the exemplary embodiment, thissecond distillation column may advantageously be relatively simple, andwell within the scope of knowledge of those of ordinary skill in theart. Because the use of the present process is expected to be useful inprocess for the production of alkylene oxide to reduce, or replace, anyamount of extraction solvent that may otherwise be added, and further, aprovide a stream of glycol ethers, the amount of which capable of beingadjusted based upon the amount of alkyl alcohol allowed to remain in thepartially refined alkylene oxide product stream the manufacturingequipment necessary to carry out the same is expected to be simplifiedas compared to the manufacturing equipment utilized to carry out theaforementioned processes. Furthermore, the process produces asubstantially pure stream of alkylene oxide and a substantially purestream of glycol ethers. And so, in another aspect, a hybridmanufacturing assembly for the production of an alkylene oxide and astream of glycol ethers is provided.

Such an assembly is shown in FIG. 1. More particularly, the assembly 100of FIG. 1 comprises a reactor 102, first distillation column 104, vessel106 and second distillation column 108. More particularly, reactor 102may comprise any reactor suitable to house the reaction to produce analkylene oxide, e.g., as from the reaction of an alkylene with hydrogenperoxide in an alkyl alcohol solvent. For example, reactor 102 may be afixed bed, a fluidized bed, or a continuous stirred tank reactor (CSTR),or a batch, semi-batch, or continuous reactor, or combinations thereof.Reactor 102 may be configured to operate isothermally, adiabatically, ora combination thereof. In some embodiments, reactor 102 comprises asupported catalyst.

Reactor 102 is operatively disposed relative to first distillationcolumn 104 so that the product stream produced therein may be receivedby distillation column 104. Distillation column 104 is furtherconfigured to receive a product stream comprising from about 5 to about15 weight percent alkylene oxide, about 50 to about 85 weight percentalkyl alcohol and about 10 to about 25 weight percent water, based uponthe total weight of the product stream, and to produce a refined streamtherefrom comprising from about 50 to about 99 weight percent alkyleneoxide, about 0.5 to about 50 weight percent alkyl alcohol and about 0 toabout 5 weight percent water. In some embodiments, e.g., wherein thealkyl alcohol comprises methanol and the alkylene oxide comprisepropylene oxide, the refined stream may comprise 65 to about 99 weightpercent alkylene oxide, about 0.5 to about 35 weight percent alkylalcohol and about 0 to about 5 weight percent water.

Advantageously, first distillation column 104 may comprise fewer than 80theoretical stages, and may comprise, e.g., from about 15 to about 70theoretical stages, or from about 30 to about 60 theoretical stages. Asis the case with reactor 102, the particular conditions at which firstdistillation column 104 is desirably operated will depend upon thecomposition of the product stream received thereby. In order to receivethe product stream and provide the refined stream defined above, and inthat exemplary embodiment wherein the alkyl alcohol comprises methanoland the alkylene oxide comprises propylene oxide, first distillationcolumn 104 will desirably be operated at a bottoms temperature of fromabout 40° C. to about 70° C., or from about 46° C. to about 64° C., orfrom about 52° C. to about 62° C. The distillation may be carried out atpressures of from about 300 mbar to about 1000 mbar, or from about 400mbar to about 800 mbar, or from about 500 mbar to about 700 mbar, asmeasured at the top of the column.

First distillation column 104 is operatively disposed to vessel 106, sothat vessel 106 may receive a refined stream therefrom. Vessel 106 maycomprise any vessel or reactor suitable to house the alkanolysisreaction, and if desired, the chosen catalyst. As such, vessel 106 maybe a fixed bed, a fluidized bed, or a continuous stirred tank reactor(CSTR), or a batch, semi-batch, or continuous reactor, or combinationsof these. Vessel 106 may be configured to operate isothermally,adiabatically, or a combination thereof. In some embodiments, vessel 106comprises a fixed bed reactor, comprising a supported metal ligandcomplex catalyst that is typically operated isothermally.

The particular conditions at which vessel 106 is operated will dependupon the particular alkyl alcohol desirably removed from the refinedstream received from distillation column 104 by vessel 106 and thecatalyst chosen to do so. For the exemplary embodiment wherein the alkylalcohol comprises methanol and the catalyst comprises a metal-ligandcomplex according to Formula I, above, vessel 106 may typically beoperated at temperatures of from about −10° C. to about 130° C., or fromabout 10° C. to about 100° C. or from about 20° C. to about 60° C., andpressures of from about 14.5 psig to about 300 psig, or from about 14.5psig to about 150, or from about 14.5 psig to about 75 psig.

A second distillation column 108 is operatively disposed relative tovessel 106 to receive a reacted stream therefrom. Second distillationcolumn is desirably configured to receive a reacted stream comprisingless than 1 wt % alkyl alcohol, from about 0.01 wt % to about 98 wt %alkylene oxide, and from about 2 wt % to about 99 wt % glycol ethers, orless than about 0.8 wt % alkyl alcohol and from about 10 wt % to about90 wt % alkylene oxide, and from about 10 wt % to about 90 wt % glycolethers, or less than about 0.7 wt % alkyl alcohol and from about 50 wt %to about 85 wt % alkylene oxide, and from about 15 wt % to about 50 wt %glycol ethers, and to produce a substantially pure stream of alkyleneoxide and a stream of glycol ethers therefrom.

The following examples are set forth for the purpose of illustrating theinvention; but these examples are not intended to limit the invention inany manner. One skilled in the art will recognize a variety ofsubstitutions and modifications of the examples that will fall withinthe scope of the invention.

Example 1. Comparative Propylene Oxide Purification Process

Propylene is converted to propylene oxide by reacting propylene withhydrogen peroxide in the presence of methanol as a solvent and TS-1catalyst (in a two stage reaction process with separation steps toremove the raw materials from the crude propylene oxide product stream.

After separation of the unreacted propylene from the effluent stream,the crude oxide stream (9.49 wt % propylene oxide, 72.38 wt % methanol,17.60 wt % water, 0.43 wt % propylene glycol methyl ether, 0.05 wt %propylene glycol, 0.01 wt % propylene, 0.03 wt % acetaldehyde, and 0.01wt % formaldehyde) is separated in a distillation stage at 0.5 bar with80 theoretical stages to obtain a top mixture comprising of propyleneoxide with less than 0.001 wt % methanol, and a bottoms mixture withless than 0.005 wt % propylene oxide. With a crude oxide feed stream of740,000 lb/hr to the tenth stage from the top of the distillation tower(typically referred to as the condenser), the separation of the purifiedpropylene oxide product can be achieved with a reflux ratio of 6.73 atthe top of the tower and 0.34 boilup ratio at the bottom of the tower(typically referred to as the reboiler). The resulting heat duty of theseparation is −33.82 Megawatt (MW) in the condenser and 41.41 MW in thereboiler.

Example 2

Propylene is converted to propylene oxide by reacting propylene withhydrogen peroxide in the presence of methanol as a solvent and TS-1catalyst in a two stage reaction process (e.g., conducted within reactor102) with separation steps to remove the raw materials from the crudepropylene oxide product stream.

After separation of the unreacted propylene from the effluent stream ofreactor 102, the crude oxide stream (9.49 wt % propylene oxide, 72.38 wt% methanol, 17.60 wt % water, 0.43 wt % propylene glycol methyl ether,0.05 wt % propylene glycol, 0.01 wt % propylene, 0.03 wt % acetaldehyde,and 0.01 wt % formaldehyde) is separated in distillation column 104 at0.5 bar with 80 theoretical stages to obtain a top mixture comprising ofpropylene oxide with 10.0 wt % methanol, and a bottoms mixture with lessthan 0.005 wt % propylene oxide. With a crude oxide feed stream of740,000 lb/hr to the tenth stage from the top of distillation column104, the separation can be achieved with a reflux ratio of 3.37 at thetop of distillation column 104 and 0.262 boilup ratio at the bottom ofdistillation column 104. The resulting heat duty of the separation is−24.48 MW in the condenser and 32.05 MW in the reboiler.

The top mixture from distillation column 104 (74,448 lb/hr) comprisingof 89.5 wt % propylene oxide and 10.0 wt % methanol is pumped to reactorvessel 106 containing the metal-ligand complex catalyst. In reactorvessel 106, the methanol reacts with the propylene oxide to form a 330:1monopropylene glycol methyl ether mixture of 1-methoxy-2-propanol (PM-2)and 2-methoxy-1-propanol (PM-1). In the isothermal reactor vessel 106,99.95% of the methanol in the reactor feed stream is converted topropylene glycol ethers. The exothermic reaction between the methanoland propylene oxide in the reactor vessel 106 requires cooling duty of−1.81 MW to maintain the reaction temperature of 60° C.

The reactor effluent stream from reactor vessel 106, consisting of 71.4wt % propylene oxide, 28.03 wt %1-methoxy-2-propanol (PM-2) and 0.08 wt% 2-methoxy-1-propanol (PM-1), is separated in distillation column 108at 0.5 bar with 25 theoretical stages to obtain a top mixture comprisingof propylene oxide with less than 0.001 wt % alcohols comprising ofmethanol and propylene glycol methyl ethers, and a bottoms mixturecomprising monopropylene glycol methyl ether with less than 0.005 wt %propylene oxide. With a feed stream of 78,448 lb/hr to the distillationcolumn 108, the separation can be achieved with a reflux ratio of 0.15at the top of distillation column 108 and 2.811 boilup ratio at thebottom of distillation column 108. The resulting heat duty of theseparation is −4.03 MW in the condenser and 3.58 MW in the reboiler.

As shown in Table 1, the total heat duty of the conventional process(75.27 MW) described in Comparative Example 1 is greater than the 66.65MW required for the inventive process, even using an 80 stagedistillation column 104 (Example 2). Table 1 also shows that the mostenergy intensive portion of the refining process is the first separationstep (at distillation column 104) where the propylene oxide isconcentrated from the mostly methanol feed material. The results inTable 1 show that the majority of the energy savings are achieved bylowering the propylene oxide purity in distillation column 104; 75.27 MWare required for 0.001% methanol (Example 1) compared to 56.53 MW for 10wt % methanol (Example 2).

Example 3

Propylene is converted to propylene oxide by reacting propylene withhydrogen peroxide in the presence of methanol as a solvent and TS-1catalyst within reactor 102 in a two stage reaction process withseparation steps to remove the raw materials from the crude propyleneoxide product stream.

After separation of the unreacted propylene in the effluent stream fromreactor 102, the crude oxide stream (9.49 wt % propylene oxide, 72.38 wt% methanol, 17.60 wt % water, 0.43 wt % propylene glycol methyl ether,0.05 wt % propylene glycol, 0.01 wt % propylene, 0.03 wt % acetaldehyde,and 0.01 wt % formaldehyde) is separated within distillation column 104at 0.5 bar with 40 theoretical stages to obtain a top mixture comprisingof propylene oxide with 10.0 wt % methanol, and a bottoms mixture withless than 0.005 wt % propylene oxide. With a crude oxide feed stream of740,000 lb/hr to the sixth stage from the top of distillation column104, the separation can be achieved with a reflux ratio of 3.89 at thetop of distillation column 104 and 0.286 boilup ratio at the bottom ofdistillation column 104. The resulting heat duty of the separation is−27.43 MW in the condenser and 35.00 MW in the reboiler.

The top mixture from distillation column 104 (74,448 lb/hr) comprisingof 89.5 wt % propylene oxide and 10.0 wt % methanol is pumped to reactorvessel 106 containing the metal-ligand complex catalyst. In reactorvessel 106, the methanol reacts with the propylene oxide to form a 330:1monopropylene glycol methyl ether mixture of 1-methoxy-2-propanol (PM-2)and 2-methoxy-1-propanol (PM-1). In the isothermal reactor, 99.95% ofthe methanol in the reactor feed stream is converted to propylene glycolethers. The exothermic reaction between the methanol and propylene oxidein reactor vessel 106 requires cooling duty of −1.81 MW to maintain thereaction temperature of 60° C.

The reactor effluent stream from reactor vessel 106, consisting of 71.4wt % propylene oxide, 28.03 wt %1-methoxy-2-propanol (PM-2) and 0.08 wt% 2-methoxy-1-propanol (PM-1) is separated within distillation column108 at 0.5 bar with 25 theoretical stages to obtain a top mixturecomprising of propylene oxide with less than 0.001 wt % alcoholscomprising of methanol and propylene glycol methyl ethers, and a bottomsmixture comprising monopropylene glycol methyl ether with less than0.005 wt % propylene oxide. With a feed stream of 78,448 lb/hr to thedistillation column 108, the separation can be achieved with a refluxratio of 0.15 at the top of distillation column 108 and 2.811 boilupratio at the bottom of distillation column 108. The resulting heat dutyof the separation is −4.03 MW in the condenser and 3.58 MW in thereboiler.

As shown in Table 1, the total heat duty of the hybrid process with thesmaller distillation column (Example 3) is less than the conventionalprocess (Example 1), but greater than the hybrid process with the 80stage column (Example 2). The lower number of theoretical trays fordistillation column 104 in Example 3 to achieve the desired separationwould significantly lower the relative capital cost for the process.

Example 4

Propylene is converted to propylene oxide by reacting propylene withhydrogen peroxide in the presence of methanol as a solvent and TS-1catalyst within reactor 102 in a two stage reaction process withseparation steps to remove the raw materials from the crude propyleneoxide product stream.

After separation of the unreacted propylene in the effluent stream fromreactor 102, the crude oxide stream (9.49 wt % propylene oxide, 72.38 wt% methanol, 17.60 wt % water, 0.43 wt % propylene glycol methyl ether,0.05 wt % propylene glycol, 0.01 wt % propylene, 0.03 wt % acetaldehyde,and 0.01 wt % formaldehyde) is separated within distillation column 104at 0.5 bar with 40 theoretical stages to obtain a top mixture comprisingof propylene oxide with 20.0 wt % methanol, and a bottoms mixture withless than 0.005 wt % propylene oxide. With a crude oxide feed stream of740,000 lb/hr to the sixth stage from the top of distillation column104, the separation can be achieved with a reflux ratio of 2.75 at thetop of distillation column 104 and 0.282 boilup ratio at the bottom ofdistillation column 104. The resulting heat duty of the separation is−26.47 MW in the condenser and 34.03 MW in the reboiler.

The top mixture from distillation column 104 (88,300 lb/hr) comprisingof 79.5 wt % propylene oxide and 20.0 wt % is pumped to reactor vessel106 containing the metal-ligand complex catalyst. In reactor vessel 106,the methanol reacts with the propylene oxide to form a 330:1monopropylene glycol methyl ether mixture of 1-methoxy-2-propanol (PM-2)and 2-methoxy-1-propanol (PM-1). In the isothermal reactor vessel 106,99.95% of the methanol in the reactor feed stream is converted topropylene glycol ethers. The exothermic reaction between the methanoland propylene oxide in reactor vessel 106 requires cooling duty of −5.16MW to maintain the reaction temperature of 60° C.

The reactor effluent stream from reactor vessel 106, consisting of 43.3wt % propylene oxide, 56.1 wt %1-methoxy-2-propanol (PM-2) and 0.16 wt %2-methoxy-1-propanol (PM-1) is separated within distillation column 108at 0.5 bar with 25 theoretical stages to obtain a top mixture comprisingof propylene oxide with less than 0.001 wt % alcohols comprising ofmethanol and propylene glycol methyl ethers, and a bottoms mixturecomprising monopropylene glycol methyl ether with less than 0.005 wt %propylene oxide. With a feed stream of 88,300 lb/hr to distillationcolumn 108, the separation can be achieved with a reflux ratio of 0.318at the top of distillation column 108 and 0.920 boilup ratio at thebottom of distillation column 108. The resulting heat duty of theseparation is −3.16 MW in the condenser and 3.26 MW in the reboiler.

As shown in Table 1, the total heat duty of the hybrid process with thesmaller distillation column with higher methanol concentration (Example4) is less than the conventional process (Example 1). The total heatduty for the process with 20% methanol in the top stream fromdistillation column 104 (Example 4) is slightly higher than with 10%methanol (Example 3). The total heat duty for the distillation column104 with 20% methanol in the top stream (Example 4) is slightly lowerthan with the same system with 10% methanol (Example 3). However, thehigher amount of methanol in the top stream from distillation column 104results in a higher heat duty for the reactor vessel 106 anddistillation column 108.

TABLE 1 Exam- Exam- Exam- Exam- ple 1 ple 2 ple 3 ple 4 Column 104Stages 80 80 40 40 Column 104 Condenser Duty −33.82 −24.48 −27.43 −26.47(MW) Column 104 Reboiler Duty 41.41 32.05 35 34.03 (MW) Reactor 106Cooling Duty −1.81 −1.81 −5.16 (MW) Column 108 Condenser Duty −4.03−4.03 −3.16 (MW) Column 108 Reboiler Duty 3.58 3.58 3.26 (MW) TotalCooling Duty (MW) −33.82 −30.32 −33.27 −34.79 Total Heating Duty (MW)41.41 35.63 38.58 37.29 Total Heat Transfer Duty 75.27 65.95 71.85 72.08(MW)

The total production rate of purified propylene oxide material is lowerwith the hybrid process due to the conversion of methanol and propyleneoxide to propylene glycol methyl ether in reactor vessel 106 between thetwo distillation columns (104 and 108) in the hybrid process. As shownin Table 2, the propylene oxide production is 20% lower than theconventional process with 10% methanol in the top stream from thedistillation column 104 (Examples 2 and 3) and 45% lower with 20%methanol (Example 4). Due to the conversion of propylene oxide topropylene glycol methyl ether in the hybrid process, the total heat dutyper unit of propylene oxide is higher with hybrid process. However, thetotal heat duty per unit of final product (propylene oxide and propyleneglycol ether) is significantly lower with the hybrid process compared tothe conventional process (Example 1).

TABLE 2 Exam- Exam- Exam- Exam- ple 1 ple 2 ple 3 ple 4 Propylene Oxide32.01 25.57 25.57 17.50 (mT/hr) Propylene Glycol Methyl Ether 10.0010.00 22.55 (mT/hr) Total Final Products 32.01 35.57 35.57 40.05 (mT/hr)Total Heat Duty 75.27 65.95 71.85 72.08 (MW) Total Heat Duty per metricton 2.35 2.58 2.81 4.12 of PO (MW/mT) Total Heat Duty per metric ton1.85 2.02 1.80 of product (MW/mT)

While only certain features of the invention have been illustrated anddescribed herein, many modifications and changes will occur to thoseskilled in the art. It is, therefore, to be understood that the appendedclaims are intended to cover all such modifications and changes as fallwithin the true spirit of the invention.

The invention claimed is:
 1. A manufacturing assembly for the productionof an alkylene oxide and one or more glycol ethers, the assemblycomprising: a reactor appropriate for housing a reaction to produce analkylene oxide product stream; an exit stream of the reactor being thealkylene oxide product stream comprising from about 5 to about 15 weightpercent alkylene oxide, about 50 to about 85 weight percent alkylalcohol, and about 10 to about 25 weight percent water; a firstdistillation column that is operatively disposed relative to the reactorand that receives the alkylene oxide product stream from the reactor,the first distillation column comprising fewer than 80 theoreticalstages; an exit stream of the first distillation column being a refinedstream comprising from about 70 to about 95 weight percent alkyleneoxide, about 1 to about 30 weight percent alkyl alcohol, and about 0.1to about 4.9 weight percent water; a vessel operatively that is disposedrelative to the first distillation column and that receives the refinedstream from the first distillation column and housing a catalyst capableof reacting with the refined stream; an exit stream of the vessel beinga reacted stream comprising reacted stream comprising less than 1 wt %alkyl alcohol, from about 0.01 to about 98 weight percent alkyleneoxide, and from about 2 to about 99 weight percent glycol ethers; and asecond distillation column that is operatively disposed relative to thevessel and that receives the reacted stream from the vessel; and anexist stream of the second distillation being a stream of alkylene oxideand a stream of glycol ethers.
 2. The manufacturing assembly of claim 1,wherein the alkylene oxide comprises ethylene oxide, propylene oxide,butylene oxide, pentylene oxide, hexylene oxide, and combinationsthereof.
 3. The manufacturing assembly of claim 1, wherein said alkyleneoxide is propylene oxide.
 4. The manufacturing assembly of claim 1,wherein the alcohol comprises methanol, ethanol, propanol, butanol,pentanol, hexanol, 2-ethylhexyl alcohol, and combinations thereof. 5.The manufacturing assembly of claim 1, wherein the alcohol comprisesmethanol.
 6. The manufacturing assembly of claim 1, wherein the catalystcomprises a metal-ligand complex, an acid, a base, or a combination ofany number of these to produce a reacted stream comprising less than 1wt % alkyl alcohol from about 0.01 to about 98 weight percent alkyleneoxide and from about 2 to about 99 weight percent glycol ethers; whereinthe metal ligand complex comprises a monomer defined by the formula:

wherein R₁, R₂, R₃, R₄, Y₁, Y₂, X₁, X₂, X₃, X₄, X₅, X₆, X₇, and X₈comprise, independently of one other, substituents selected from thegroup consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl,hydrocarbyl, hydroxyl, alkoxyl, amino, nitro, amide, phosphoryl,phosphonate, phosphine, carbonyl, carboxyl, silyl, ether, thioether,sulfonyl, selenoether, ketone, aldehyde, and ester; or wherein two ormore of R₁, R₂, R₃, R₄, Y₁, Y₂, X₁, X₂, X₃, X₄, X₅, X₆, X₇, and X₈together form a ring selected from the group consisting of a carbocyclicring and a heterocyclic ring, said ring having from 4 to 10 atoms in thering; wherein R₅ group is selected from the group comprising acarbon-carbon bond, a methylene group, an ethylene group, an amine, anoxygen atom, and a sulfur atom; wherein M^(t+) is a Group 2-15 metalcapable of complexing with a ligand to affect catalysis, wherein t is aninteger between 2 and 4; wherein group A is selected from the groupconsisting of neutral group, bound anionic group, unbound anionic group,and combinations thereof, wherein s is the number of A groups associatedwith the metal and is an integer between 0 and 2.